Software modem with privileged mode decryption of control codes

Abstract

A communications system includes a physical layer hardware unit and a processing unit. The physical layer hardware unit is adapted to communicate data over a communications channel in accordance with assigned transmission parameters and receive an incoming signal over the communications channel and sample the incoming signal to generate a digital received signal. The processing unit is adapted to execute a standard mode driver in a standard mode of operation and a privileged mode driver in a privileged mode of operation. The standard mode driver includes program instructions adapted to extract encrypted data from the digital received signal and pass the encrypted data to the privileged mode driver. The privileged mode driver includes program instructions adapted to decrypt the encrypted data to generate decrypted data including control codes and transfer the control codes to the physical layer hardware unit.

1. A communications system, comprising:
 a physical layer hardware unit adapted to communicate data over a communications channel in accordance with assigned transmission parameters, the physical layer hardware unit being adapted to receive an incoming signal over the communications channel and sample the incoming signal to generate a digital received signal; and 
 a processing unit adapted to execute a standard mode driver in a standard mode of operation and a privileged mode driver in a privileged mode of operation, wherein the standard mode driver includes program instructions adapted to extract encrypted data from the digital received signal and pass the encrypted data to the privileged mode driver, and the privileged mode driver includes program instructions adapted to decrypt the encrypted data to generate decrypted data including control codes and transfer the control codes to the physical layer hardware unit, the physical layer hardware being adapted to configure its assigned transmission parameters based on the control codes. 
 
   
   
     2. The system of  claim 1 , wherein the control codes include at least one of a power level assignment, a frequency assignment, and a time slot assignment. 
   
   
     3. The system of  claim 1 , wherein the privileged mode of operation comprises a system management mode of operation. 
   
   
     4. The system of  claim 1 , wherein the standard mode driver includes program instructions adapted to issue a signal to the processing unit to initiate a change from the standard mode of operation to the privileged mode of operation. 
   
   
     5. The system of  claim 4 , wherein the signal comprises a system management interrupt. 
   
   
     6. The system of  claim 1 , wherein the processing unit includes a memory device adapted to store the encrypted data, and the standard mode driver includes program instructions adapted to pass a pointer indicating a location of the encrypted data within the memory device to the privileged mode driver. 
   
   
     7. The system of  claim 1 , wherein the privileged mode driver includes program instructions adapted to extract user data from the decrypted data and pass the user data to the standard mode driver. 
   
   
     8. The system of  claim 7 , wherein the processing unit includes a memory device adapted to store the user data, and the privileged mode driver includes program instructions adapted to pass a pointer indicating a location of the user data within the memory device to the standard mode driver. 
   
   
     9. The system of  claim 1 , wherein the privileged mode driver include program instructions adapted to encrypt the control codes and pass the encrypted control codes to the standard mode driver, the standard mode driver includes instructions adapted to send the encrypted control codes to the physical layer hardware unit, and the physical layer hardware unit is adapted to decrypt the encrypted control codes to reconstruct the control codes. 
   
   
     10. The system of  claim 1 , wherein the privileged mode driver includes instructions adapted to transfer the control codes directly to the physical layer hardware unit. 
   
   
     11. The system of  claim 1 , wherein the processing unit comprises a computer. 
   
   
     12. The system of  claim 11 , wherein the computer includes:
 a processor complex adapted to execute the program instructions in the standard mode driver and the privileged mode driver; 
 a bus coupled to the processor complex; and 
 an expansion card coupled to the bus, the expansion card including the physical layer hardware. 
 
   
   
     13. The system of  claim 1 , wherein the processing unit includes a system basic input output system (BIOS) memory adapted to store the privileged mode driver. 
   
   
     14. The system of  claim 13 , wherein the processing unit is adapted to load the privileged mode driver from the system BIOS into a protected memory location during initialization of the computer. 
   
   
     15. A method for configuring a transceiver, comprising:
 receiving encrypted data over a communications channel in a standard processing mode of a processing unit; 
 transitioning the processing unit into a privileged processing mode; 
 decrypting the encrypted data in the privileged processing mode; 
 extracting control codes from the decrypted data in the privileged processing mode; and 
 transmitting an upstream signal over the communications channel based on transmission assignments defined by the control codes. 
 
   
   
     16. The method of  claim 15 , wherein transmitting the upstream signal comprises transmitting the upstream signal based on at least one of a power level assignment, a frequency assignment, and a time slot assignment. 
   
   
     17. The method of  claim 15 , wherein transitioning the processing unit into the privileged processing mode comprises a transitioning the processing unit into a system management mode of operation. 
   
   
     18. The method of  claim 15 , wherein transitioning the processing unit into the privileged processing mode comprises initiating a system management interrupt. 
   
   
     19. The method of  claim 15 , further comprising specifing a pointer indicating a location of the encrypted data within a memory device of the processing unit. 
   
   
     20. The method of  claim 15 , further comprising sending the control codes to a communications device adapted to transmit the upstream signal in the privileged processing mode. 
   
   
     21. The method of  claim 15 , further comprising:
 encrypting the control codes in the privileged processing mode; 
 transitioning the processing unit into the standard processing mode; and 
 sending the encrypted control codes to a physical layer device adapted to transmit the upstream signal in the standard processing mode. 
 
   
   
     22. The method of  claim 21 , further comprising:
 decrypting the encrypted control codes in the physical layer device; and 
 configuring the physical layer device based on the control codes. 
 
   
   
     23. The method of  claim 15 , further comprising:
 extracting user data from the decrypted data in the privileged processing mode; 
 transitioning the processing unit into the standard processing mode; and 
 processing the user data in the standard processing mode. 
 
   
   
     24. The method of  claim 23 , further comprising specifying a pointer indicating a location of the user data within a memory device of the processing unit. 
   
   
     25. A modem, comprising:
 means for receiving encrypted data over a communications channel in a standard processing mode of a processing unit; 
 means for transitioning the processing unit into a privileged processing mode; 
 means for decrypting the encrypted data in the privileged processing mode; 
 means for extracting control codes from the decrypted data in the privileged processing mode; and 
 means for transmitting an upstream signal over the communications channel based on transmission assignments defined by the control codes.